Most people want to be liked - but all too often this need to feel appreciated and admired can draw us into saying "yes" when actually we really mean "no". Roy Leighton has devised this straightforward exercise to help you increase your assertiveness.

Always saying "yes" when you mean "no" is a surprisingly easy habit to get into. However, if you always behave in the same way, you'll never get anywhere new. This exercise will help you get off that treadmill. We all have the power to change our patterns of behaviour and become what we want.

This is a good group exercise, but can also be effective as a one-on-one session. It's better not to do it on your own, as the whole point is to modify your response to others. It also uses the 'Pendulum effect'. It allows you to go to the opposite extreme of where - or who - you usually are so that somewhere along the line a 'middle way' can be found.

• Imagine a scenario in the past where you have said "yes" but meant "no". Explain to the group or your exercise partner what the situation was, what the outcome was and how you felt.
• Ask your partner to ask you the question that you should have said "no" to. This needs to be one sentence.
• It shouldn't turn into a debate! We're not looking for the person asking the question to give a convincing argument of why they need a "yes". As soon as they start to ask the question, interrupt and say clearly and loudly: "NO!".
• If there are several people in the group, get them to form a line. Each person should begin to ask you: "Can you stay late at work tonight?" or "Mum, please can you help me do this?" - and so on. As soon as you have said "no" they must go to the back of the queue.
• If there are just two of you, then the questioner receives the "no", steps away and then steps back and asks again.
• With each request your "no" has to become more and more determined, blunt and even rude. Whether you're working in pairs or as part of a group, the questions should come thick and fast, in as many ways as you can imagine.
• This exercise can go on for at least 30 "nos". Once you've finished, jot down on a piece of paper how you feel. Focus on the positive feelings you're experiencing. Keep this piece of paper with you.
• The next time you feel like saying "yes" remember your feelings and how you felt writing down those words. Feel free to say "no". Back it up with a short, reasonable explanation if necessary, but if you mean "no" then let it be heard!

Remember, it's often the case that people treat us as we feel we deserve to be treated. Once we make it clear first to ourselves, and then through our actions to others that the rules have changed, then people will change the way they treat you as a matter of course. With dedication you can become the person you want to be.